Challenges in measuring energy expenditure in companion animals: a clinician's perspective

Standard recommendations as to how much to feed dogs and cats are based on the average requirements of unstressed healthy laboratory dogs and cats of normal body condition undertaking modest amounts of exercise in a thermoneutral environment, but most clinical patients do not conform to these norms. Most clinicians estimate the energy expenditure of patients using a factorial calculation that adjusts for any differences from the norm, but little information exists upon which to base these adjustments. Furthermore, individual variation in energy expenditure is substantial even in dogs and cats under closely defined physiological conditions, and the estimate of energy expenditure obtained by using a factorial calculation can differ by a substantial margin from the energy expenditure of an individual. Detailed dietary histories provide an estimate of individual energy requirements but are time consuming to perform and rely on several assumptions. There are also no readily available point-of-care methods for measuring the energy expenditure of dogs and cats. There is a need, therefore, for further research concerning factors that affect energy expenditure of dogs and cats and methods of measuring energy expenditure in individual patients.